Two speed high shift transmission

ABSTRACT

The present invention employs a hydraulically operable piston and intermediate member to control two clutches in a first planetary gear set. The first planetary gear set includes a first sun gear, a first planet gear, a first planet carrier and an inner ring gear. The first planet carrier includes a gear which drives a second planetary gear set resulting in rotation of a wheel hub. With hydraulic pressure applied to the piston and the intermediate member a first clutch is engaged locking an inner ring gear to a stationary outer ring effecting a high ratio reduction. With no hydraulic pressure applied to the piston and intermediate member a second clutch engages the first sun gear and the first planet carrier locking them together such that the first sun gear, first planet gear, first planet carrier and inner ring gear rotate in unison effecting a low ration reduction. With no hydraulic pressure applied, the first clutch is not engaged.

BACKGROUND OF THE INVENTION

The instant invention is a hydraulically controlled transmission.Specifically, the instant invention is a hydraulically controlledtwo-speed transmission residing primarily within a rotatable wheel hub.Air or gas may be used to control the transmission instead of hydraulicoil if desired. The transmission includes a spindle which is affixed tothe frame of a vehicle. An outer ring is affixed to the spindle suchthat the outer ring is stationary. The transmission provides for twospeed reductions. Two planetary gear sets are employed to accomplish thetwo speed reductions. The transmission is suitable for use onagricultural vehicles and truck cranes and generally those machines thatwork off road and travel on road. It will be appreciated by thoseskilled in the art that the invention is not limited to transmissionsresiding primarily within a rotatable wheel hub.

SUMMARY OF THE INVENTION

Commercially available clutches are employed in the transmission. Afirst clutch and a second clutch are employed in the first planetarygear set. A first sun gear, a first planet gear, a first planet carrier,an inner ring gear and a stationary outer ring are employed in the firstplanetary gear set. The preferred embodiment of the present inventionemploys a first planetary gear set having three first planet gears. Itwill be understood by those skilled in the art that more or fewer firstplanet gears may be employed. By speed reduction it is meant that theoutput of the transmission is reduced such that the output rotates oncefor multiple rotations of the input. Speed reduction is stated as aratio of input rotations to output rotations.

The first planet carrier is the input to a second sun gear of a secondplanetary gear set. The second planetary gear set has second planetgears, a second planet carrier and a wheel hub in addition to theaforementioned second sun gear. The preferred embodiment of the presentinvention employs a second planetary gear set having three planet gears.It will be understood by those skilled in the art that more or fewersecond planet gears may be employed. The wheel hub is affixed to thesecond planet carrier. The stationary outer ring includes an internalgear for engagement with the second planet gears.

The preferred embodiment of the present invention includes two speedreductions, or ratios. The low ratio, approximately 6.6 to 1 (6.6:1),and the high ratio, approximately 41 to 1 (41:1), are effected by theunique and novel clutch control apparatus described in detailhereinbelow. The aforestated ratios are input to output ratios. Thefirst sun gear is the input and the wheel hub is the output. Thus forthe low ratio of 6.6 to 1, the first sun gear makes approximately 6.6revolutions for a single output revolution of the wheel hub. Similarlyfor the high ratio of 41 to 1, the first sun gear makes approximately 41revolutions for a single revolution of the output wheel hub.

The low ratio (6.6:1) is effected when the first sun gear and the firstplanet carrier are locked together by the second clutch. The firstclutch is disengaged when the low ratio is effected. The high ratio(41:1) is effected when the stationary outer ring and the inner ringgear are locked together by the first clutch. The second clutch isdisengaged when the high ratio is effected.

The instant invention includes a piston and an intermediate member tocontrol the clutches. The piston and intermediate member arehydraulically operated. A spring is disposed between a spring stopaffixed to the intermediate member and the piston. Those skilled in theart will recognize that the spring stop could easily be integrallyformed with the intermediate member. Shoulder surfaces on the stationaryouter ring are also employed in the control of the clutches.

The control of the clutches as set forth in detail hereinbelow is noveland unique. It will, of course, be appreciated by those skilled in theart that the apparatus employed to control the clutches as set forthherein can be used to effect a plurality of speed reductions. Differentspeed reductions are achievable by using different first and secondplanetary gear sets.

It is an object of the invention to provide an intermediate member, aspring, a bearing, and shoulders on the stationary outer ring incombination with the piston for controlling the second clutch lockingthe first sun gear to the first planet carrier. The piston and theintermediate members are in their respective first positions when thesecond clutch locks the first sun gear to the planet carrier. The firstsun gear, first planet carrier and inner ring gear all rotate togetherin unison when the first sun gear and first planet carrier are lockedtogether by the second clutch. The first planet carrier is the output tothe second sun gear. Thus, when the second clutch is engaged asaforestated the first planetary gear set does not effect a reduction asviewed from the first sun gear to the first planet carrier. In otherwords, the first sun gear (input) rotates at a 1:1 ratio with respect tothe first planet carrier (output).

It is a further object of the invention to provide a hydraulicallyoperable piston for controlling the first clutch locking the inner ringgear to the stationary outer ring. The piston and the intermediatemember are in their respective second positions when the first clutchlocks the inner ring gear to the stationary outer ring. The firstplanetary gear set effects a reduction when the inner ring gear islocked to the stationary outer ring.

It is a further object of the invention to: hydraulically control theengagement of the first clutch; primarily mechanically control theengagement of the second clutch; and to hydraulically control thedisengagement of the second clutch.

It is a further object of the invention to employ a first clutch havingfirst and second sets of clutch plates and a second clutch having firstand second sets of clutch plates. The second clutch includes separatorsprings which reside between the first and second clutch plates of thesecond clutch. It is a further object to mechanically (through theseparator springs) assist the disengagement of the second clutch.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an enlarged sectional view of the first planetary gear settogether with the first and second clutches. FIG. 1 illustrates thefirst, larger clutch engaged locking the outer ring and the inner ringgear together and the second, smaller clutch disengaged. FIG. 1illustrates the condition when pressure is applied to the cavity whichis bounded by the piston and the intermediate member. The piston and theintermediate member are shown in FIG. 1 as being in their respectivesecond positions. FIG. 1 additionally illustrates the clutches effectinghigh ratio (41:l)speed reduction.

FIG. 2 is an enlarged sectional view of the first planetary gear settogether with the first and second clutches. FIG. 2 illustrates thefirst, larger clutch disengaged and the second, smaller clutch engagedlocking the first sun gear together with the first planet carrier. FIG.2 illustrates the condition when no pressure is applied to the cavitywhich is bounded by the piston and the intermediate member. The pistonand the intermediate member are shown in FIG. 1 as being in theirrespective first positions. FIG. 2 additionally illustrates the clutcheseffecting low ratio (6.6:1) reduction.

FIG. 3 is a (top) sectional view of the first and second planetary gearsets, the spindle, the outer ring, and the wheel hub. The piston and theintermediate member are shown in FIG. 3 as in FIG. 2 in their respectivefirst positions. In FIGS. 2 and 3, the first sun gear, the first planetgear and the first planet carrier all rotate together at equalrotational speed. Put another way the first sun gear rotates in a 1:1ratio with the first planet carrier. Therefore, no speed reduction iseffected by the first planetary gear set and the first planet carrierdrives the second sun gear effecting low ratio reduction, approximately6.6:1, first sun gear: wheel hub.

FIG. 4 is a (top) sectional view of the first and second planetary gearsets, the spindle, the outer ring and the wheel hub. The piston andintermediate members are shown in FIG. 4, as in FIG. 1, in theirrespective second pistons. In FIGS. 1 and 4, the first planet carrierrotates at a reduced speed with respect to the first sun gear effectinghigh ratio reduction, approximately 41:1, first sun gear: wheel hub.

FIG. 5 is a (bottom) sectional view of the first and second planetarygear sets, spindle, first and second clutches, piston, intermediatemember, and the outer ring. FIG. 5 illustrates the second clutch engagedeffecting low ratio reduction as shown in FIGS. 2 and 3. FIG. 5additionally illustrates means for retaining the outer ring to thespindle.

FIG. 6 is a further enlarged sectional view of the intermediate member,piston, spring, spring stop, hydraulic (or air/gas) passageways andcavity. FIG. 6 illustrates the piston and intermediate members in theirrespective second positions.

FIG. 7 is a further enlarged sectional view of the intermediate member,piston, spring, spring stop, hydraulic (or air/gas) passageways andcavity. FIG. 7 illustrates the piston and intermediate member in theirrespective first positions.

The drawings will be better understood when taken in conjunction withthe following description of the preferred embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The control of the first and second clutches 16, 47 is novel and unique.The first clutch 16 comprises a first set 17 of clutch plates and asecond set 18 of clutch plates. The first set 17 of clutch plates engagean outer ring 12. The second set 18 of clutch plates engage arotationally movable inner ring gear 19. Abrasive material 70 on clutchplates 18 is illustrated in FIG. 2. A first clutch backing plate 58 issupported and kept in place by a snap ring 22. This provides a rigidsupport against which the first clutch is operated or engaged.

A spindle 57 is secured to a vehicle or other frame (not shown). Thespindle 57 can be fixed to the vehicle frame through a number ofconventional mountings, for example, bolting, welding, etcetera. Theouter ring 12 is affixed to the spindle and is, therefore, stationarywith respect to the vehicle. FIGS. 3, 4 and 5 illustrate the outer ring12 affixed to spindle 57 by means of spindle spline 87 and outer ringspline 88. Splines 87, 88 prevent rotational movement of the outer ring12 with respect to the spindle 57. Support plate 86 and bolt 85 preventlongitudinal movement of outer ring 12 with respect to spindle 57.

The second clutch 47 comprises a first set of plates 50 and a second setof plates 52. The first set of plates 50 engage a planet carrier 49. Thesecond set 52 of plates engages a collar 61 which is locked to a firstsun gear 51. The collar 61, sometimes referred to by those skilled inthe art as a coupling, is affixed to the first sun gear 51 by means ofspline 89. The first sun gear has a mating spline 120 which engagesspline 89 of the collar 61. Abrasive material 71 on clutch plates 52 isillustrated in FIG. 1.

The collar 61 is a sleeve-like member which resides around the shaft 91of the first sun gear 51. Retaining ring 90 provides a stop for thecollar 61 to prevent longitudinal movement of the collar 61 with respectto the shaft of the first sun gear 51 in one direction. The shaft 91includes threads 125 engageable with threaded nut 124 for adjusting thelongitudinal position of collar 61.

A first backing plate 62 is locked to collar 61 by means of a firstbacking plate spline 97 and a spline 121 of collar 61, which preventsrotation of the first backing plate relative to collar 61. Retainingring 98 prevents longitudinal movement of the first backing plate towardfirst planet gear 48. The second backing plate 63 includes a spline 122for mating with spline 121 on collar 61. This prevents rotation of thesecond backing plate relative to the collar 61. The first backing plate62 allows a movable second backing plate 63 to engage the first set ofclutch plates 50 and the second set of clutch plates 52 together lockingthe first sun gear 51 and the first planet gear carrier 49 together.

The second clutch 47 further includes separator springs 53 forseparating the first and second sets of clutch plates 50, 52. Theseparator springs 53 mechanically assist the disengagement of the secondclutch 47 when proper as will be discussed below. The separator springs53 additionally provide residual force on the intermediate member 35 aswill discussed below.

The outer ring 12 includes a first shoulder 14, best viewed in FIG. 6and a second shoulder 13, best viewed in FIG. 7. Additionally, thestationary outer ring 12 includes a passageway 15 and a port 32.Stationary outer ring 12 is generally cylindrically shaped and includesan interior surface 92 and an exterior surface 93. Port 32 comprises acircumferential recess in the interior surface of the stationary outerring 12.

Spindle 57 includes a passageway 80 which communicates with passageway15 of the stationary outer ring 12. A hydraulic pump or pressure source(not shown) and a control system (not shown) supply hydraulic oil to thepassageways 15 and 80 as will be discussed in detail below. The controlof the hydraulic supply system either supplies pressure to thepassageways and port 32 or it does not supply pressure to thepassageways and port 32. The hydraulic supply control system is,therefore, either on or off.

The first sun gear 51 includes a shaft 91 and gear teeth 68. Firstbearings 73 support the first sun gear 51 with respect to the spindle57. The shaft 91 further includes threads 94. Adjusting means 69 operatein conjunction with the threads 94 for longitudinal positioning thefirst sun gear 51. See FIGS. 3 and 4.

The control of the clutches 16, 47 is effected by a piston 20, anintermediate member 35, a spring 28, a bearing 45, a first 14 and asecond 13 shoulder of the stationary outer ring 12. The first planetarygear set comprises a first sun gear 51, a first planet gear 48, a firstplanet carrier 49 and an inner ring gear 19. The inner ring gear 19includes internal gear teeth 66. The planet gear 48 or gears 48 includegear teeth 67 and the first sun gear 51 includes gear teeth 68. The gearteeth 67 of the planet gear 48 engage or mesh with the teeth 68 of thesun gear and the teeth 66 of the inner ring gear.

The first planet gear 48 is mounted on shaft 95. Pin 65 restrainsmovement of the shaft 95 relative to the first planet carrier 49. Theplanet gear 48 includes bearings 64 which allow the planet gear torotate about shaft 95. The first planet carrier 49 includes an internalspline 96. The internal spline 96 is the output of the first planetarygear set to the secondary planetary gear set, namely the second sun gear54.

The control of the first and second clutches is novel and unique. Thepiston 20, intermediate member 35, spring 28, bearing 45 and first andsecond shoulders 14, 13 combine in the control of the clutches. Thepiston 20 includes a first end portion 21 for engaging the first clutch16, an intermediate portion 23 and a second end portion 24. The piston20 further includes a first shoulder 25 on the intermediate portion 23thereof. The piston still further includes an interior 99 and anexterior 111. The interior 99 of piston 20 includes a shoulder 26thereon. The second end portion 24 of piston 20 includes a flat, plannerface 27. It will, of course, be appreciated by those skilled in the artthat the face 27 need not necessarily be a flat, planar surface.

The stationary outer ring 12 includes first and second recesses 30, 31,which along with first and second seals provide for sealing about port32. The seals are elastomeric seals. Similarly, second end portion 24 ofthe piston 20 includes a recess 29 which along with elastomeric seal 112provides for sealing between piston 20 and the intermediate member 35.

The intermediate member 35 includes a first end portion 36, a second endportion 37, and an intermediate portion 39. The second end portion ofthe intermediate member includes a flat planar surface 38. Theintermediate member 35 includes a first shoulder 44 having a firstsurface 59 and a parallel, spaced-apart second surface 60.

The intermediate member 35 is generally cylindrically shaped and has ashaft which extends from the first end portion 36 to the intermediateportion 39 thereof. The shaft 113 of the intermediate member has asurface 114.

The intermediate member includes a washer 42 affixed thereto. Snap ring41 supports and affixes washer 42 to the intermediate member 35. Washer42 includes a surface 43 upon which spring 28 rests. The spring 28 isdisposed between surface 43 of washer 42 and shoulder 26 of the piston.

The intermediate member 35 has a second shoulder 46 on the intermediateportion thereof. Bearing 45 resides between the second shoulder 46 andthe movable second backing plate 63 splined to collar 61. Separatorsprings 53 assist in ensuring engagement of the bearing between theintermediate member and the second backing plate at all times.

Face 27 of the piston 20, shoulder 44 and surface 114 of intermediatemember 35, and port 32 define a cavity 11. When the cavity 11 ispressurized with hydraulic oil through passageways 15 and 80, the piston20 and intermediate member 35 are in their respective second positionsas illustrated in FIGS. 1, 4 and 6. When the cavity is not pressurized,the piston and intermediate members are in their respective firstpositions as illustrated in FIGS. 2, 3, 5 and 7. The preferredembodiment of the present invention provides for ensuring that cavity 11is sufficiently open to effect the hydraulic pressurization thereof.FIGS. 2, 3, 5 and 7 illustrate that the parallel, spaced apart surfaces59, 60 ensure that hydraulic fluid will always have entrance to at leastthe space between surface 59 of the intermediate member and the flat,planar face 27 of the piston. Thus even in the instance that the surface60 might engage the face 27 of the piston, cavity 11 will be open forpressurization. In the instance that face 27 does engage surface 60 ofthe intermediate member, cavity 11 is defined by the volume betweensurface 59 and face 27 plus the volume in port 32.

Piston 20 and intermediate member 35 are, themselves, generallycylindrically shaped as is illustrated by FIGS. 3, 4 and 5. Port 32extends around the interior of the outer ring. Therefore, sufficientcavity volume for pressurizing is present.

The first planet carrier 49 is the input to the second planetary gearset. The second planetary gear set includes a second sun 54, a secondplanet gear 115 or gears 115, a second planet carrier 55 and an internalgear 77 on outer stationary ring 12. The second planet carrier isaffixed to wheel hub 56 by bolts 78. Therefore, the second planetcarrier and the wheel hub 56 rotate in unison. Second bearings 74support the wheel hub 56 around the stationary outer ring 12 and spindle57. Seal 72 prevents unwanted leakage of lubricants between the wheelhub 56 and spindle 57.

The second planet gear 115 includes teeth 83. The shafts 114 are lockedto the second planet carrier by pins 82. Second planet gears 115 aremounted on shafts 114 by bearings 81. The planet gears 115 are,therefore, free to rotate about shafts 114. Teeth 78 of planet gear 115mesh with teeth 84 of the second sun gear 54. Similarly, teeth 78 ofplanet gears 115 mesh with the teeth 77 of the stationary outer ring 12.

Thrust plates 75 and 76 are employed in the present invention to absorbthrust loads imparted to the first and second sun gears. The first andsecond sun gears rotate about the same axis of rotation. A brake means79 is employed to externally brake the wheel hub when desired.

The unique and novel clutch control is now explained in detail. Thereare two conditions, modes or states of operation. The first condition iswhen there is no hydraulic pressure applied through passageways 15 and80 to cavity 11. The second condition is when hydraulic pressure isapplied through passageways 15 and 80 to cavity 11.

FIGS. 2, 3, 5 and 7 illustrate the first condition, to wit, no hydraulicpressure applied to cavity 11. The piston 20 and intermediate member 35are in their first positions. The first shoulder 25 of the pistonengages the first shoulder 14 of the stationary outer ring 12. Spring 28urges the first shoulder 44 of the intermediate member toward the face27 of the piston 20.

Intermediate member 35 and bearing 45, under the force of coil spring28, urge the second backing plate 63 into engagement with the clutch 47.The first and second sets of clutch plates of clutch 47 engage the firstplanet carrier 49 and collar 61. The first planet carrier is locked tothe collar 61 which, in turn, is locked to shaft 91 of the first sungear. No speed reduction is effected in the first planetary gear setunder this condition. This results in the low ratio reduction ofapproximately 6.6:1. In this condition the first sun gear 51, firstplanet carrier 49 and the inner ring gear 19 are all locked together androtate in unison. The first clutch is disengaged and the inner ring gearis free to rotate independent from the outer ring.

FIGS. 1, 4 and 6 illustrate the second condition, to wit, hydraulicpressure applied. The piston 20 and intermediate member are in theirsecond positions. The second shoulder 38 of the intermediate member 35engages the second shoulder 13 of the stationary outer ring 12. Thehydraulic pressure urges the second end portion 21 of the piston intoengagement with the first clutch 16 locking the outer ring 12 to theinner ring gear 19. The inner ring gear 19 is thus a reaction gear inthis condition. Spring 28 is compressed between the shoulder 26 of thepiston 20 and the surface 43 of washer 42. Washer 42 and snap ring 41are sometimes referred to herein as a spring-stop.

The second clutch is disengaged by the application of hydraulicpressure. Separator springs 53 urge the first and second plates of thesecond clutch apart urging the intermediate member 35 into engagementwith the second shoulder 13. The intermediate member 35 in thiscircumstance is urged into engagement with the outer ring by thehydraulic pressure applied in the cavity 11 and by the force of theseparator springs 53 transmitted through the bearing 45 and the movablebacking plate 63.

In the pressurized condition a speed reduction is effected in the firstplanetary gear set. This results in the high ratio reduction ofapproximately 41:1.

The first clutch is hydraulically applied and spring released. Thismeans that the instant pressure is relieved from the system, andnecessarily from the face 27 of the piston, the first clutch 16 willimmediately disengage. The piston will move under the force of thespring 28 until it engages the first shoulder of the stationary outerring.

Although this invention has been described in its preferred form andpreferred practice with a certain degree of particularity, it isunderstood that the disclosure has been made by way of example and thatnumerous changes in the details of construction and the combination andarrangement of parts and steps may be resorted to without departing fromthe spirit and scope of the invention as hereinafter claimed.

What is claimed is:
 1. A transmission comprising an inner ring gear and a stationary outer ring, a first sun gear, said first sun gear having a splined collar affixed thereto, a first planet gear and a first planet carrier, a first clutch operable between said inner ring gear and said outer ring, a second clutch operable between said first sun gear and said first planet carrier, a piston moveable between first and second positions, an intermediate member moveable between first and second positions, a spring, said intermediate member includes a spring stop affixed thereto, said spring disposed between said piston and said spring stop affixed to said intermediate member, a bearing, said bearing residing between said intermediate member and said second clutch, said piston, said spring, said intermediate member and said bearing forceably effecting engagement of said second clutch locking said first sun gear and said first planet carrier together when said piston and said intermediate member are in their respective first positions, and, said piston engaging said first clutch locking said inner ring gear and said outer ring together and said intermediate member and said bearing effecting disengagement of said second clutch unlocking said first planet carrier and said first sun gear when said piston and said intermediate member are in their respective second positions.
 2. A transmission as claimed in claim 1 further including means for application of hydraulic pressure to said face of said piston and said shoulder of said intermediate member.
 3. A transmission as claimed in claim 1 wherein said piston includes a face and said intermediate member includes a shoulder and wherein said stationary outer ring includes a passageway and a port, said passageway and said port communicating with said face of said piston and said shoulder of said intermediate member.
 4. A transmission as claimed in claim 3 wherein said passageway and said port communicate hydraulic pressure to said face of said piston and said shoulder of said intermediate member.
 5. A transmission as claimed in claim 4 wherein said first clutch includes a first and second set of clutch plates and said second clutch includes a first and second set of clutch plates, said second clutch further includes separator springs disposed between said first and second clutch plates.
 6. A transmission as claimed in claim 5 wherein no hydraulic pressure is communicated to said face of said piston and said shoulder of said intermediate member and said piston and said intermediate member are in their respective first positions.
 7. A transmission as claimed in claim 5 wherein hydraulic pressure is communicated to said face of said piston and said shoulder of said intermediate member and said piston and said intermediate member are in their respective second positions.
 8. A transmission as claimed in claim 7 wherein said stationary outer ring includes first and second shoulders, said intermediate member includes first and second end portions and an intermediate portion, and said second end portion of said intermediate member engages said second shoulder of said stationary outer ring.
 9. A transmission as claimed in claim 6 wherein said stationary outer ring includes a first shoulder, said piston having an intermediate portion, said intermediate portion of said piston includes a first shoulder, said first shoulder of said piston engaging said first shoulder of said stationary outer ring.
 10. A transmission as claimed in claim 9 wherein said intermediate member includes first and second end portions and an intermediate portion, said first end portion of said intermediate member having said spring stop affixed thereto, said piston having a second shoulder, said spring residing between said spring stop and said second shoulder of said piston urging said intermediate member and said piston to their said respective first positions.
 11. A transmission as claimed in claim 8 wherein said intermediate member includes first and second end portions and an intermediate portion, said first end portion of said intermediate member having said spring stop affixed thereto, said piston having a second shoulder, said spring residing between said spring stop and said second shoulder of said piston, said piston and said intermediate member being in their second respective positions and said spring being compressed by said piston and said spring stop affixed to said intermediate member.
 12. A transmission as claimed in claim 11 wherein said spring is partially compressed.
 13. A transmission as claimed in claim 5 further comprising a plurality of first planetary gears.
 14. A transmission as claimed in claim 13 wherein said first planet carrier includes an internal spline.
 15. A transmission as claimed in claim 14 further comprising a spindle, said spindle being affixed to a vehicle frame, said stationary outer ring affixed to said spindle.
 16. A transmission as claimed in claim 15 further comprising a second sun gear, a second planet gear, a second planet carrier, and a hub, said stationary outer ring includes an internal gear, said hub being affixed to said second planet carrier.
 17. A transmission as claimed in claim 16 further comprising a plurality of said second planet gears, said first sun gear having an axis of rotation, said second sun gear having an axis of rotation coincident with said axis of rotation of said first sun gear, and said hub being supported by a plurality of bearing permitting rotation of said hub about said axes of rotation of said first and second sun gears.
 18. A two-speed vehicle transmission comprising an inner internal ring gear and a stationary outer ring, said stationary outer ring includes first and second shoulders, a first sun gear a plurality of first planet gears and a first planet carrier, said first planet carrier being generally cylindrically shaped, a first clutch operable between said inner internal ring gear and said outer ring, said first clutch having a first set of plates for engagement with said outer ring and a second set of plates for engagement with said inner internal ring gear, a second clutch operable between said first sun gear and said first planet carrier, said second clutch having a first set of plates for engagement with said first planet carrier and a second set of plates for engagement with said first sun gear, a piston hydraulically moveable between first and second positions, an intermediate member hydraulically moveable between first and second positions, said piston being generally cylindrically shaped and having an interior and an exterior, said piston having first and second end portions, said second end portion of said piston terminating in a planar face, said first end portion of said piston engaging said first clutch, said intermediate member having first and second end portions and an intermediate portion, said intermediate member having a shoulder on said intermediate portion thereof, said planar face of said piston and said shoulder on said intermediate portion of said intermediate member having approximately equal surface areas, said piston having a first shoulder on said exterior thereof, said piston having a second shoulder on said interior thereof, a spring, said first end portion of said intermediate member having a spring stop affixed thereto, said spring disposed between said second shoulder of said piston and said spring stop, a bearing, said bearing residing between said intermediate member and said second clutch, said first shoulder of said piston engages said first shoulder of said stationary outer ring and said second clutch locks said first sun gear and said first planet carrier together when said piston and said intermediate member are in their respective first positions with no hydraulic pressure applied to said face of said piston and said shoulder of said intermediate member, and, said second shoulder of said intermediate member engages said second shoulder of said stationary outer ring and said first clutch locks said inner ring gear and said outer ring together and said second clutch unlocks said first planet carrier and said first sun gear when said piston and said intermediate member are in their respective second positions with hydraulic pressure applied to said face of said piston and said shoulder of said intermediate member.
 19. A two-speed hydraulic transmission as claimed in claim 18 further comprising a second sun gear, a plurality of second planet gears and a second planet carrier, said first planet carrier includes an internal spline which drives said second sun gear, said stationary outer ring includes an internal gear for engagement with said second planet gears, a hub, said hub affixed to said second planet carrier, said first sun gear and said second planet carrier and said hub rotating at an approximate 6.6:1 ratio with no hydraulic pressure applied to said face of said piston and said shoulder of said intermediate member; said first sun gear and said second planet carrier and said hub are rotating at an approximate 41:1 ratio with hydraulic pressure applied to said face of said piston and said shoulder of said intermediate member.
 20. A two-speed hydraulic transmission as claimed in claim 19 further comprising means for braking said hub.
 21. A transmission comprising an inner ring gear and a stationary outer ring, a first sun gear, a first planet gear and a first planet carrier, a first clutch operable between said inner ring gear and said outer ring, a second clutch operable between said first sun gear and said first planet carrier, a piston movable between first and second positions, an intermediate member moveable between first and second positions, a spring disposed between said piston and said intermediate member, a bearing, and, said bearing residing between said intermediate member and said second clutch, said piston, said spring, said intermediate member and said bearing forceably effecting engagement of said second clutch locking said first sun gear and said first planet carrier together when said piston and said intermediate member are in their respective first positions, and, said piston engaging said first clutch locking said inner ring gear and said outer ring together and said intermediate member and said bearing effecting disengagement of said second clutch unlocking said first planet carrier and said first sun gear when said piston and said intermediate member are in their respective second positions.
 22. A transmission as claimed in claim 21 wherein said piston includes a face and said intermediate member includes a shoulder, and wherein said piston and said intermediate members are hydraulically moveable.
 23. A transmission as claimed in claim 21 wherein said piston includes a face and said intermediate member includes a shoulder, said face of said piston includes first and second surfaces, and wherein at least one of said surfaces of said piston is spaced apart from said shoulder of said intermediate member forming a cavity therebetween.
 24. A transmission as claimed in claim 23 wherein said cavity is hydraulically pressurized.
 25. A transmission as claimed in claim 22 wherein said piston, in said first position, disengages said first clutch unlocking said inner ring gear from said stationary outer ring, and, said intermediate member, in said first position, in combination with said bearing engages said second clutch locking said first sun gear and said first planet carrier.
 26. A transmission as claimed in claim 25 wherein said piston and said intermediate member are in their respective first positions with no hydraulic pressure on said face of said piston and said first shoulder of said intermediate member.
 27. A transmission as claimed in claim 22 wherein said first clutch includes first and second plates, and, said second clutch includes first and second plates and separator springs residing between said first and second plates.
 28. A transmission as claimed in claim 27 wherein said piston, in said second position, engages said first clutch locking said stationary outer ring to said inner ring gear, and said intermediate member in combination with said separator springs, in said second position, disengages said second clutch unlocking said first sun gear and said first planet carrier.
 29. A transmission as claimed in claim 28 wherein said piston and said intermediate member are in their respective second positions with hydraulic pressure on said face of said piston and said first shoulder of said intermediate member.
 30. A transmission as claimed in claim 26 wherein said first planet carrier includes an internal spline.
 31. A transmission as claimed in claim 29 wherein said first planet carrier includes an internal gear.
 32. A transmission as claimed in claim 30 further comprising a plurality of planet gears and a spindle, said stationary outer ring being affixed to said spindle.
 33. A transmission as claimed in claim 31 further comprising a plurality of planet gears and a spindle, said stationary outer ring being affixed to said spindle.
 34. A transmission as claimed in claim 32 further comprising a second sun gear, a second planet gear, and a second planet carrier, a hub, said hub affixed to said planet carrier.
 35. A transmission as claimed in claim 34 wherein said internal spline of said first planet carrier drives said second sun gear.
 36. A transmission as claimed in claim 33 further comprising a second sun gear, a second planet gear, and a second planet carrier, a hub, said hub affixed to said planet carrier.
 37. A transmission as claimed in claim 36 wherein said internal spline of said first planet carrier drives said second sun gear.
 38. A transmission as claimed in claim 35 wherein said stationary outer ring is an internal gear.
 39. A transmission as claimed in claim 37 wherein said stationary outer ring is an internal gear.
 40. A transmission as claimed in claim 32 wherein said first sun and said first planet carrier rotate together in a 1:1 ratio
 41. A transmission as claimed in claim 38 wherein said first sun and said hub and said second planet carrier rotate at an approximate 6.6:1 ratio.
 42. A transmission as claimed in claim 39 wherein said first sun and said hub and said second planet carrier rotate at an approximate 41:1 ratio.
 43. A transmission as claimed in claim 41 further including a plurality of first and second bearings and wherein said first sun gear is supported by a plurality of said first bearings disposed between said first sun gear and said spindle and where said hub is supported by a plurality of said second bearings disposed between said stationary outer ring and said hub.
 44. A transmission as claimed in claim 42 further including a plurality of first bearings and second bearings and wherein said first sun gear is supported by a plurality of said first bearings disposed between said first sun gear and said spindle and wherein said hub is supported by a plurality of said second bearings disposed between said stationary outer ring and said hub.
 45. A transmission as claimed in claim 43 further comprising an external brake means operable against said hub.
 46. A transmission as claimed in claim 44 further comprising an external brake means operable against said hub.
 47. A transmission as claimed in claim 1 further including adjusting means longitudinally positioning said splined collar with respect to said sun gear.
 48. A transmission as claimed in claim 1 wherein said sun gear includes a shaft, said shaft include a spline for mating with said splined collar, said shaft includes threads, and, a threaded nut for engaging said threads on said shaft for longitudinally positioning said splined collar with respect to said sun gear. 